Hi Martin,
I've had a look around our instrument driver network database (http://www.ni.com/devzone/idnet/) and unfortunetly I can't find any support for DCX instruments.
DCX themselves may have some driver software for it so it would be worth contacting them to see but unfortunetly there doesn't seem to be anything on our website.
If you can't get hold of a driver for it then you should still be able to program with it using LabVIEW as long as you have access to the command set. Most instruments will respond to calls from a DLL file, so you can call this file using the Call Library Function node and then pass parameters to and from it as you need.
Hope this helps,
Best regards,
Peter H.
Applications Engineer.
NIUK.